PRUNUS PERSICA Stokes.

1.P. Persica Stokes Bot. Mat. Med. 3:100. 1812.
2.P. Persica var. vulgaris Maximowicz Mel. Biol. 11:668. 1883.
3.P. Persica var. necturina Maximowicz l. c. 669. (nectarine)
4.P. Persica var. laevis Gray
5.P. Persica var. nucipersica Dippel Handb. Laub. 3:606. 1893. (nectarine)
6.P. Persica var. platycarpa Bailey Cyc. Am. Hort. 1456. 1901. (Flat Peach, Peento)
7.Amygdalus Persica Linnaeus Sp. Pl. Ed. 1:472. 1753.
8.A. Persica var. nucipersica Linnaeus l. c. 676. (nectarine)
9.A. nectarina Aiton Hort. Kew Ed. 2, 3:194. 1811. (nectarine)
10.A. Nuci-persica Reichenbach Fl. Germ. Exc. 647. 1832. (nectarine)
11.A. laevis Dietrich Syn. Pl. 3:42. 1852. (nectarine)
12.Persica vulgaris Miller Gard. Dict. Ed. 8: No. 1. 1768.
13.P. nucipersica Borkhausen Forstb. Beschrb. 205. 1790. (nectarine)
14.P. laevis De Candolle Fl. Fran. 4:487. 1805. (nectarine)
15.P. platycarpa Decaisne Jard. Fr. Mus. (Pechers) 42. 1872-75. (Flat Peach, Peento)

Tree low, attaining a height of thirty feet, diffuse, open-headed, broad-topped, often without a central leader; trunk at maturity sometimes a foot in diameter; bark dark reddish-brown, in old trees rough and scaly; branches spreading, slender and sometimes drooping; twigs round, rather slender, glabrous, glossy green changing to shades of red, with numerous, large or small, conspicuous, usually raised lenticels.

The leaves are alternate, simple, four to seven inches long, one to two inches wide, broad-lanceolate or more often oblong-lanceolate; upper surface dark green, smooth, dull or shining, some rugose along the midrib; lower surface paler, with little or no pubescence; apex long-tapering, base abrupt or acute; margins coarsely or finely serrate, or crenate, sometimes doubly toothed, teeth tipped with glands or sometimes glandless; petioles stout, from a quarter-inch to an inch long, grooved, glandless or more often with from one to eight globose or reniform glands, sometimes mixed, a part of which may be on the base of the leaf.

The flowers develop from scaly buds on the wood of the previous season; flower-buds plump, conical or obtuse, free or appressed and usually appearing before the leaves; flowers of two distinct sizes, with some intermediates, the smaller size ranging under an inch in diameter, the larger, an inch and a half or more; the floral color ranges from an occasional pure white through shades of pink to deep red; fragrant and always pleasantly so; pedicels very short, sometimes seemingly wanting, glabrous, green; calyx-tube urn-shaped, usually smooth but sometimes pubescent without, green overlaid with red outside, greenish-yellow or dark orange within; calyx-lobes five in number, short, broad, glabrous within, pubescent without; petals ovate, five in number, rounded at the apex which is sometimes notched, tapering to a claw, sometimes notched at the base; stamens twenty to thirty, about one-half inch long, slender, distinct, usually colored; anthers yellow; ovary sessile, pubescent, one-celled, surmounted by a simple style which is terminated with a small stigma, the whole pistil equaling the stamens in length or longer.

Fruit a fleshy drupe, sub-globular but much modified in shape and size under cultivation; suture usually distinct; cavity well marked, abrupt; apex with a mamelon or mucronate tip; color varying from greenish-white to orange-yellow, usually with a red cheek on the side exposed to the sun, sometimes covered with red; very pubescent except in the nectarine; skin adherent or free from the pulp; flesh greenish-white or yellowish, often stained with red at the pit, occasionally red, sweetish, acidulous, aromatic; stone free or clinging, elliptic or ovoid, sometimes flat, compressed, pointed; outer surfaces wrinkled and pitted, inner surfaces polished; ventral and dorsal sutures grooved or furrowed, sometimes winged; the seed almond-like, aromatic, bitter.

The characters given in the foregoing description are those of the cultivated peach—the consummate fruit of Prunus persica. The generic name, Prunus, is the ancient Latin name of the plum, Prunus domestica, the type species. The specific name, persica, commemorates the old belief that the peach came from Persia. The common name, peach, in English, as in most European languages, is a derivative from persica. Amygdalus, found several times in the synonomy, is the Syrian name of the almond. The drupe-fruits are put in two, three and sometimes four genera by various botanists but in the fruit-books issued by this Station, following most botanists and pomologists, all are put in a single genus, Prunus. Such lumping of several distinct fruits into one genus has its disadvantages but the several fruits cannot be reasonably separated because outliers closely connect all. Hybridization between the cultivated stone-fruits adds to the perplexities of classification.

Prunus persica is variously divided by botanists and pomologists. Quite commonly two botanical varieties of edible peaches are split off, as shown in the synonomy, to separate the nectarine and the flat peaches from the pubescent and globular peaches. But these sub-species, originating over and over in the case of the nectarine as a bud or seed-mutation and the flat peaches probably having originated as a mutation, are not more distinct from the parent species than the red-fleshed sorts, the snowball peaches, the Yellow Transvaals from South Africa, the nippled peach, the cleft peach, the beaked peach, the winter peaches of China, or the pot-grown dwarfs from China; in fact, are not more different from other peaches than a clingstone is from a freestone, a yellow flesh from a white flesh or a large-flowered from a small-flowered sort. All constitute merely pomological groups, which, more and more, are becoming interminably confused by hybridization.

ALTON (Large Flowered)

BLOOD LEAF

We name but one sub-species of Prunus persica, and that doubtful. Mr. Frank N. Meyer of the United States Department of Agriculture has recently introduced into the United States cuttings of a wild peach from the province of Kansu, China, which he thinks has horticultural value. The peach is Prunus persica potanini Batalin (Act. Hort. Petrop. 12:164. 1892) which Mr. Meyer describes as follows:[168]

"A wild peach of the davidiana type, but differing from it in various points. Collected at the base of sheltered mountains at an elevation of 4300 feet. A tall shrub or even small tree, up to 30 feet in height, bark of stem or trunk dark reddish-brown and quite smooth in the younger shoots; leaves like those of Amygdalus davidiana but often broader in the middle and always less pointed. Fruits of round-elongated form; skin covered with a heavy down, no edible flesh; stones of elliptical shape, grooves longer than in A. davidiana, shells very hard and thick, kernels elongated and relatively small. Found growing at elevations from 4000 to 7000 feet, in side valleys away from the Siku river; thrives especially well in sheltered and warm mountain pockets. Of value especially as a stock for stone-fruits and possibly able to stand even more dry heat than A. davidiana; also recommended as an ornamental spring-flowering tree, especially for the drier parts of the United States. Chinese name Mao t'ao, meaning 'hairy peach.'"

There are many ornamental forms of the peach-tree—sorts with single or double flowers, white, pink or red in color, normal, red or variegated foliage and standard or dwarf trees. The best-known named ornamental peaches are camelliaeflora with large, carmine flowers and its sub-variety, plena, with double flowers; versicolor with different colored flowers on branches of the same tree; atropurpurea with brownish-red foliage; foliis rubris, similar or possibly the same as the preceding, the color in both extending to the fruit; magnifica, a semi-double with brilliant carmine-crimson flowers; pyramidalis, a pyrimidal form; pendula, a weeping peach; and still others, of the distinctness of which we cannot be certain, as dianthi-alba-plena, rubro-plena, and coccineo-plena. With these ornamentals we are not to be further concerned.

Of Japanese garden-forms the following varieties have been described: P. Persica var. densa Makimo Tokyo Bot. Mag. 16:178. 1902. P. persica var. vulgaris, f. stellata Makimo l. c. 22:119. 1908. P. Persica var. vulgaris, f. praematura Makimo l. c. 22:119. 1908.

Species are but convenient groups, their limits reflecting the judgment of the species-maker. Were the authors of this text to divide Prunus persica, the cleavage lines would be other than those indicated in the foregoing paragraphs. Prunus persica might be divided, though there is no intention of furthering confusion by the addition of new names, into two species. One would include the white-fleshed, clingstone peaches, with large flowers and calyx greenish-yellow inside; the other the yellow-fleshed, freestone peaches, with small flowers and calyx-cups orange inside. Primitive forms in China indicate such a division, the evolution of varieties suggests it and the present disposition of the characters named as separating these theoretical species attest the reasonableness of such a separation. The primitive forms have been described and the descent of varieties may be traced in the last two chapters, so that we need only amplify the statement as to the present disposition of characters.

The characters in the two hypothetical species have been thoroughly shuffled by hybridization but even if there is not correlation, as there certainly is between color in calyx-cup and color of flesh, it might be expected that those associated in the primitive plant, the Adam of the race, would, despite the shuffling, still be most often associated. What are the facts? In the Station orchard are 109 white-fleshed peaches; 40 per ct. of these are semi-cling or clingstones leaving 60 per ct. nearly or quite free (there is constant selection for freestones); 64 per ct. have large flowers; all have calyx-cups yellowish-green inside. There are in this orchard 106 yellow-fleshed peaches; but 17 per ct. of these are cling or semi-cling, the remainder being either quite free or nearly so; 73 per ct. have small or medium-sized flowers; all have calyx-cups deeply colored with orange inside.

Similarities in characters indicate so close a relationship between the almond and the peach that one might well suspect many hybrids between the two. Yet there appear to be but few clear cases of peach and almond crosses. Knight[169] reports crossing the two, the doubtful results of which led him to believe, as we have seen, that the peach is but a modified almond. Several such crosses are indicated in botanical literature[170] but whether all refer to one or several supposed crosses there is no way of knowing—probably to one. The almond blooms so much earlier than the peach that crosses could hardly occur in nature. A hybrid between the two from which could be evolved a late-blooming almond is a consummation to be wished.

CHINESE FREE (Medium Flowered)

CROSBY (Small Flowered)